<?php
 /*
 用法：
 aes::encrypt($str,$key);
 aes::decrypt($str,$key);
 */
class aes {
    public static function encrypt($str, $key) {
        $size = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_ECB);
        $str = self::pkcs5_pad($str, $size);
        $td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');
        $iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
        mcrypt_generic_init($td, $key, $iv);
        $data = mcrypt_generic($td, $str);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        $data = base64_encode($data);
        $src = ["/","+"];
        $des = ["_","-"];
        $data = str_replace($src,$des,$data);
        return $data;
    }
 
    private static function pkcs5_pad($str, $blocksize) {
        $pad = $blocksize - (strlen($str) % $blocksize);
        return $str . str_repeat(chr($pad), $pad);
    }
 
    public static function decrypt($str, $key) {
    	$src = ["_","-"];
    	$des = ["/","+"];
    	$str = str_replace($src,$des,$str);
    	
        $decrypted= mcrypt_decrypt(MCRYPT_RIJNDAEL_128,$key,base64_decode($str),MCRYPT_MODE_ECB);
        $dec_s = strlen($decrypted);
        $padding = ord($decrypted[$dec_s-1]);
        $decrypted = substr($decrypted, 0, -$padding);
        return $decrypted;
    }
}


